Jan 29 (Reuters) - Colgate-Palmolive Co on Thursday reported a rise in an important sales metric, sending its shares up 6 percent as investors shrugged off a lowered earnings forecast.

The consumer products maker, which controls nearly 45 percent of the global toothpaste business, said fourth-quarter organic sales, which exclude the effects of foreign exchange, acquisitions and divestments, rose 6 percent because of higher volumes and better pricing.

Chief Executive Officer Ian Cook said on a conference call that sales volumes increased in all emerging markets despite the price hikes Colgate took to offset a strengthening dollar.

Cook also said Colgate expected gross profit margins to increase by 50 to 100 basis points in 2015 as it benefits from lower prices for oil and other commodities.

In the fourth quarter, gross margin fell 30 basis points to 58.8 percent from a year earlier due to higher raw material and packaging costs stemming in large part from unfavorable currency fluctuations.

Net sales suffered because of the strong dollar and weak demand in markets such as Brazil and Europe.

Cook said foreign exchange volatility would remain a challenge in 2015.

The rise in the dollar over the past nearly nine months has reduced the value of overseas sales. A stronger dollar also makes U.S.-made products more expensive for consumers in other currencies and lowers demand.

Rival Procter & Gamble Co said on Tuesday that it no longer expected sales and core earnings to grow this year, blaming a strong dollar for its disappointing results and forecast.